This invention relates generally to heat pumps and more particularly to a heat pump with potable water heating capability.
In the past, heat pump systems have typically been split systems with an outdoor unit containing the compressor, heat exchange coil and a fan and an indoor unit including an air circulation blower and a heat exchange coil. More recently, potable water heat exchange coils have been added to the heat pump system so that domestic hot water can also be heated. Still more recently, the outdoor refrigerant-to-air heat exchange coils have sometimes been replaced by a refrigerant-to-liquid heat exchange coil so that an external liquid could be used as a source to heat or cool for this heat exchange coil. Typically, this source of heating/cooling is ground water or a ground loop water circuit.
With the advent of non-air heat exchange coils to replace the normal outdoor coil, there is no necessity that any of the components of the system be located outside. Some attempts have been made to incorporate the refrigerant-to-liquid heat exchange coils and the compressor in a single cabinet housing the indoor unit. One of the problems associated with these attempts is that the size of the resulting unit is larger than the original indoor unit so that, in retrofit applications, the ductwork had to be modified in order to incorporate these units. Further, in updraft situations where the unit is housed in small utility closets with the return air duct in the floor and the supply air duct in the ceiling, the prior art simply has not been able to provide a retrofit unit without significantly modifying the ductwork associated with the utility closet.